


Oh Little Brother

by ArchOfImagine



Series: Prompt Ficlets [3]
Category: Supernatural
Genre: Blow Jobs, Brothers making bets, Frottage, Kink Meme, M/M, Prompt Fic, Semi-Public Sex, Size Kink, mentions of bottom Sam
Language: English
Status: Completed
Published: 2017-05-25
Updated: 2017-05-25
Packaged: 2018-11-04 17:30:32
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,385
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10995594
Author URL: https://archiveofourown.org/users/ArchOfImagine/pseuds/ArchOfImagine
Summary: The brothers compare dick sizes... winner gets the last slice of Dean's birthday cake.





	Oh Little Brother

**Author's Note:**

> A fill for [this prompt](http://spnkink-meme.livejournal.com/121551.html?thread=43400655#t43400655) over at the kink meme. Hopefully the original poster accepts my sacrifice. :D

“Gotta piss, man,” Dean grumbled, rousing from sleep in the passenger seat of the Impala. They had been driving for literal _hours_ and Dean had finally succumbed and let Sam take the wheel about three hours back, since they were in the middle of bum-fuck Wyoming without a reliable motel to stop at — or even the cash to cover a room fee.

It was almost dawn, the sky to the east was starting to brighten, and the road they were on had been deserted for hours. Finding an old access road to one of the many farms they were passing by, Sam pulled the car off the road and put her in park. When Dean stepped out of the car, he stretched out his long limbs and looked over to where his brother was also climbing out. 

When Sam saw his quirked eyebrow, he shrugged, “Might as well go too, while we’re stopped.”

Dean gave a half nod and moved to the front of the car, so that Baby’s big black body would block him from sight in the absolutely rare instance that another car passed by. As he was unzipping his pants and pulling his dick out, he felt his brother step up beside him and rolled his eyes.

“Is not a urinal,” he mumbled, still feeling half asleep. “Ain’t gotta be up in my business.”

Sam, not lagged by sleep worn movements, already had his dick out and was holding the base as he started to piss. “You’re just worried that you’ll see my dick and realize I’m not just the tallest.”

Over the sound of his own bladder beginning to empty, Dean stated simply, “ _You wish._ ”

His little brother nudged his elbow. “Bet you the last slice of birthday cake that it is.”

Dean frowned, remembering the lone slice of _raspberry filled poppy seed cake with cream cheese frosting_ that was sitting happily in their old green cooler with Dean’s name on it. It had been _his_ birthday, after all.

He shook off the last few drops of pee and turned to face his brother, already beginning to stroke his cock. They hadn’t fought over size differences since Sam was eight years old… “You’re on. Full mast, we’ll line ‘em up like we used to.”

Sam turned to him as well, already half hard and smirking as he stroked himself, “I think I’ll lick the plate after I finish my slice of cake…”

Stepping closer into his little brother’s space, Dean shook his head, “My birthday, my cake, little brother.”

Sam gave him a look that clearly said he had no doubt he was going to win, then stepped forward into Dean’s personal space and looked down at his hard cock. Dean did the same, lining up his dick next to his brother’s and immediately groaning when he realized that Sam had a good inch on him in length… not to mention the larger girth. _Mother fucker._ When had his baby brother got so big? How did he fuck anything without splitting it in half?

He looked up to see a twinkle in those familiar hazel eyes, “Double or nothing, for the last beer too,” Dean growled. “Anything goes, I bet you come first.”

His younger brother rocked his hips forward, causing his dick to just barely slide along Dean’s length. “Anything goes?”

“You heard me.”

With a sly look, Sam happily continued the rocking, making sure that he wrapped his large hand ( _fuck_ , was every part of him ginormous? Why hadn’t Dean noticed?) around both of their cocks and stroked in rhythm. 

_Shit._ What a monstrously bad idea this whole mess had been… Dean let his head dip back for a moment and enjoyed the feelings because it had been way too long since someone else had touched his dick. When he lifted his head and looked back at his brother, he saw that smug grin and realized that Sammy boy thought he was going to win Dean’s cake. 

Time to up the ante.

Leaning closer, Dean breathed gently along the side of his brother’s neck. With his left hand, he rucked Sam’s shirt up until he could tweak a nipple. His right hand found another path. After a gentle squeeze at an amazingly shaped hipbone, he moved his hand down to gently fondle his brother’s balls. When he heard Sam let out a breathy hiss, he gave his own smirk and licked a strip along his neck. Sam’s position shifted, spreading his legs out as far as the pants around his ankles would allow for… giving Dean _more room._

Dean bit back a growl, rocked his cock against his brother’s, and let a couple of fingers start slowly inching a path back. At the first brush of his index finger around Sam’s hole, Sam jerked, eyes closed and hand stalling a bit on the stroking.

_Fuck._ All of that cock and… Dean bit lightly on Sam’s earlobe before whispering, “Pretty little _bottom._ ”

“Deeeeannn,” Sam managed, stretching out his brother’s name. 

He felt the slick slide of their cocks rubbing start to get a little smoother and looked down to see Sam’s dick leaking precome like it was going out of style. Another swirl of that one finger, another pinch of a hard nipple, and then, “Want me to fuck you, little brother? Rock deep inside… hit that good spot that makes you see stars?” His voice was a gravelly mess, still harshly whispering in Sam’s ear.

“Please,” Sam moaned.

“That’s it.” Dean moved his left hand down to lay on top of Sam’s where it was grabbing both of their cocks. He applied a little pressure and began guiding Sam’s hand back and forth. “Beg for my cock, _Sammy._ ”

The tip of a blunt fingernail dipped ever so slightly into his brother’s hole, and suddenly Sam’s entire body was quivering as he came — and if Dean thought Sam’s cock was big, it was nothing compared to the amount of come that the damn thing sprayed all over his lower abdomen. Dean pulled back a step, moving both hands up to hold Sam’s shoulders and make sure that his brother came down from his orgasm okay.

When Sam seemed to be recovered, he looked at Dean with a heated gaze, before pulling his pants up and then dropping down into the dirt at Dean’s feet. Dean was just about to make a snide comment in regards to how terrible a time it was to tie his shoe… when Sam leaned forward and slowly began _licking his own come off of Dean’s dick._

“Oh holy shit,” Dean gasped, one hand reaching out to land on the Impala’s hood, while the other curled into Sam’s hair. Up until that very moment, it was all just a dumb game (well, he could tell himself it was, at least), but suddenly everything was _too real_ and Dean felt like his brain was going to explode. When Sam had skillfully cleaned up all of the come, he moved to the tip of Dean’s cock, looked up with heat in his hazel eyes, and held Dean’s gaze as he slowly swallowed him down.

Hit little brother knew how to deepthroat.

Good fucking God.

“I can’t—” He gasped, rocking his hips ever so slightly as his head fell back, “Can’t last, Sammy.”

Sam’s response was an elongated moan around the length of Dean’s cock and he was _done._ The orgasm hit him so hard he almost lost his balance, as he cried out and emptied himself quickly into his brother’s mouth. 

Again, Sam made sure that he meticulously cleaned up every drop of come, and when he was done, Dean grabbed his collar and pulled him to his feet, not wasting a moment before crashing his mouth against his brother’s.

He could taste both of their spent seed as he let his tongue explore his brother’s mouth; too very distinct flavors that blended too perfectly together. 

When the kiss broke, Dean smiled, lazy and a bit hazed from his orgasm. “‘M gonna lick that cake off of every inch of you, little brother.”

Sam smirked, leaning forward to lick along Dean’s ear, much the same way that Dean had been a few minutes before. “Promises, promises,” he growled…

… and Dean felt his dick give a _very_ interested twitch.


End file.
